During the past years, the evolution of networking has been driven by intertwining the need of increased capacity with the need of flexibility and fault tolerance. In spite of ongoing standardization efforts, the variation of the communication requirements for the commercially available devices has continuously increased. Therefore, network routers and switches require a large number of physical network interfaces in order to be able to interconnect various network devices within the same network or to intermediate connection with other networks. Network-based applications frequently use communication sessions via physical network interfaces extensively.
The Open System Interconnection (OSI) model is a coherent work-frame for network communication developed by the International Organization for Standardization (ISO). In the OSI model, a communication system is divided in a hierarchy of (seven) layers, each layer being a collection of conceptually similar functions that provide services to the layer above and receives services from the layer below. In other words, an instance of an intermediate layer provides services to instances of layers above and requests services from instances of layers below. The seven layers of the OSI are illustrated in FIG. 1: The Physical layer 10, the Data Link layer 20, the Network layer 30, the Transport layer 40, the Session layer 50, the Presentation layer 60 and the Application layer 70.
Thus, the Physical layer 10 and the Data Link layer 20 are the lowest layers in this OSI model. The Physical layer 10 defines electrical and physical specifications for network devices, performing functions for establishment and termination of a connection to a communication medium, modulation or conversion between the representation of data in user equipment and the corresponding signals transmitted over a communications channel, etc. The Data Link layer 20 provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the Physical layer 10.
Commercially available devices are configured to provide Physical layer functions (i.e., PHY devices) or Data Link functions (i.e., MAC devices). These devices may communicate based on standard interface specifications, at relatively small distances (e.g., between 7-50 cm) based on copper technologies. Thus, the devices may be physically separated (allowing more flexibility in system and board designs) and interconnected through a crossbar device. The use of a reconfigurable crossbar device enables dynamically reassigning the links between any PHY and MAC devices.
Dynamically reassigning the links between PHY and MAC devices via a reconfigurable crossbar renders the system fault tolerant. However, when this reassignment is performed according to traditional methods, a large number of packets are lost. It is desirable to avoid or even to eliminate the loss of packets particularly during hardware and software upgrades or while an advanced energy management function is executed.
Accordingly, it would be desirable to provide devices, systems and methods that perform dynamic (run-time) reassignment of PHY and MAC devices interconnect with minimal or no packet loss.